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Posted by: Dr Evil Jul 2 2007, 12:09 AM

This weekend has been very productive! All of my vehicles are at least turing fuel into noise. Now it is time to make it useful.

I put the fuel pump back in my Benz (it was out because I thought it was problematic). I adjusted the lever that actuates it and it now starts, but it runs rough.
-White smoke
-Knocks more than a diesel should
-Has no power (less then before )

I made sure to NOT crank the engine with the pump removed and to keep the pump shaft from rotating so as to keep the orientation of the shafts in both correct. I may be off a little in my adjustment, but adjusting it will be a shitty task and I would like some veriffication that it is out of adjustment from someone more knowledgable than I before I go a bleeding all over the engine again.

In summary:
- Do the symptoms scream of any particular problem?
- any advice?

Thanks all!

Posted by: Mr.C Jul 2 2007, 12:18 AM

How long did you run it? Sounds to me like it may still have some air in the lines. I had the same symptons on my 6.2 after I changed the injection pump until it cleared out. Seen the same symptons many times in the past when I serviced old farm tractors. They all did what you described until the air purged through.

Posted by: Dr Evil Jul 2 2007, 12:26 AM

Realy? Man that would be awsome. Should I just let it run for a while then? How long? I didnt run it long.

Posted by: brer Jul 2 2007, 12:32 AM

bleed the fuel lines.
check that the small bleed off lines are connected and not leaking.

white not blue smoke?

Posted by: Mr.C Jul 2 2007, 12:38 AM

Yeah, if it'll stay running let it go until it clears through. It may take a minute or sometimes longer. I took the whole pump off of mine thinking I made the mistake of missaligning it. Did it for nothing it just had an extremely bad case of air in the lines. It took a few minutes to clear up. My memory of the frustration is returning.

Posted by: Dr Evil Jul 2 2007, 12:41 AM

Whitish.

I'll give it some time to run. It was parked on an incline and all the fuel was out of the lines. It worried me because it was shaking soo bad and sounded loud.

Posted by: Mr.C Jul 2 2007, 12:49 AM

Yeah that definately sounds like air in the lines to me. Shaking is a sympton of air not letting the injectors hit.

Posted by: Dr Evil Jul 2 2007, 12:56 AM

If your right I am gonna give you a beer

Posted by: brer Jul 2 2007, 01:09 AM

sounds like you need to drive it really hard uphill.
that always worked for me.

Posted by: Dr Evil Jul 2 2007, 01:13 AM

I will flog it arround the complex tomorrow and report back

Posted by: messix Jul 2 2007, 03:05 AM

here's my RX for the good Dr! http://mbca.cartama.net/

Posted by: Paul Illick Jul 2 2007, 03:20 AM

White smoke? Just for giggles once it's running take off the radiator cap and make sure there aren't any bubbles blowing up through the coolant.

Posted by: bottomend Jul 2 2007, 04:36 AM

White smoke is usually the sign of air in the fuel lines as stated above. I'm not familiar with MB but some cars have a really hard time purging air from their systems if they have a "closed loop" fuel system. Some guys install an air bleed valve in the line for this purpose.

Posted by: bottomend Jul 2 2007, 04:37 AM

That would be very bad. It's not a common problem with MB's right? I have a ford 7.3 IDI and it's the song of death for these.

Posted by: BiG bOgGs Jul 2 2007, 06:25 AM

If you think it is air in your lines, the simple procedure is to just crack the fuel lines where they meet the tops of the injectors. This will allow the compressible air to escape from the line between the pump and the injector. Be careful when you loosen the nut holding the line, because the fuel that is under high pressure can spray out hard enough to puncture your skin if you are right at the point of the leak. When you see clean diesel and no bubbles escaping from the nut, just tighten it back down and you should hear the engine smooth (for a diesel) and run like it should.

Jim

Posted by: BMartin914 Jul 2 2007, 07:27 AM

White smoke and rough running can also be an indication that your pump is over advanced.

Be careful with running the engine (at all, especially under load) unless you have verified for certain that your timing is correct.

Posted by: Dr Evil Jul 2 2007, 09:52 AM

How do I verify this? How far would make a difference; the pump is only off one tooth one way or the other and the teeth are pretty fine (many of them/small adjustment). Total allowable adjustment on the pump is about 10*

If it is off of adjustment, how do I know when it is in?

I am very certain that I have air in the lines as the pump was out of the car, empty, and the car was parked up hill causing any residual gas to pool back in the tank. I used the hand primer to get it started (took a looooong time). I can crack the fuel lines, I know they had air in them as they were left on the pump.

Messix, unfortunately that forum is hard to get info out of on a 75 115, IIRC I can try again.

Posted by: Dr Evil Jul 2 2007, 10:44 AM

Oh ya, another tid bit of info that may lean your oppinions one way or the other.

When I had it sitting and was holding constant pedal it was kind of pulsating (not rhythmically, though) for lack of a better term. Rough, quiet, rough, etc. Also, when it is idling it is very mildly oscillating (wwAAwwAAwwAAA, ya know )

Still sounds like out of time? Air? Makes no difference, run it and see what happens?

Posted by: messix Jul 2 2007, 12:17 PM

air.
in high school i worked for a rental yard that rented out dozers, loaders and backhoes,. home owners would rent this equipment out and regularly run an diesel powered equipment out of fuel, then put gas in it. long story short i was pretty quick at draining the tank and purging the fuel injector pump and priming the inject lines.
don't run it any more than it takes to bleed the injectors, diesel are under a lot of stress as it is and having irregular ignition pulses can shorten the life of that little rattle can.

Posted by: BiG bOgGs Jul 2 2007, 12:20 PM

Sorry Dr., I should have said to crack the lines open at the injectors while the engine is running. This will allow the fuel to purge the air in the lines and then when you retighten the lines it should immediately run smoother. If you crack a line and retighten it and the sound of the engine doesn't change at all you may have a problem with that injector.

My diesel engine experience comes from swapping a VW 1.6L Turbo D into my Suzuki Samurai. With the VW's the timing is set by using a dail indicator attached to an opening in the rear of the injection pump. Then the pump is moved toward the engine to advance the timing, or away to retard. Whith most for these engines being pretty old, it is usually best to adjust the pump, run the engine and see how it sounds, then re-adjust until you get it where you want. I would find out how the timing is adjusted on your engine, and then play a bit.

After you have it sounding right you can keep an eye on your temp readings to see if it is set right. If your oil temps get pretty high and your exhaust temps are low, you are probably on the advanced side of the timing. If you have high exhaust temps and lower oil temps (and probably less power) you are running too retarded.

Posted by: Dr Evil Jul 2 2007, 12:28 PM

So, when the injectors are clear....stop running it?
How long should I wait for it to clear?

I'll try the crack the line method. Seems straight forward. Adjusting the pump is not an easy task. There are only 3 nuts, but the bottom one is blocked by the primer pump...which has 2 nuts that are hard to get to holding it on....and requires blood to get off...and oil and gas goes everywhere This was not supposed to be a project car

Posted by: BiG bOgGs Jul 2 2007, 12:32 PM

He means not to run it until you are ready to purge the lines. Start it up and get to work. When you are done purging (this is sounding like and anorexia forum) the engine should be running properly.

Posted by: Brian Mifsud Jul 2 2007, 12:37 PM

Have you checked the fuel pump timing? I just sold off my 240D stuff, including the fuel event timing nozzle. To change timing, you need a crowbar.. (I love the Germans).... You loosen the mounting nuts, then pry on the pump using the block as a fulcrum. Advance/Retard as needed, the fuel lines will fight against the pump moving (they are rigid tubing), so you will need to slightly "overbend" to get the right position. Timing virtually NEVER changes, it really just necessary when you change a fuel line, or pull the pump (if the lines get bent while pump is off).

gotta love mechanical injection

Posted by: BiG bOgGs Jul 2 2007, 12:38 PM

Another thought.

If you do the purge and still find it running a little off, check around the fuel lines for a leak (between the pump and the injectors) that may be causing the injector to not have enough pressure to open properly. Do this with a scrap of cardboard. Having a high pressure stream of diesel tear your skin and mix with your blood is not fun.

Posted by: brer Jul 2 2007, 01:08 PM

Actually, the germans would rather you unscrew the metal fuel lines. Adjust the pump properly, then spend 3 hours bending the metal lines to match the new pump timing.

The crowbar method I believe was an american invention.

Posted by: Dr Evil Jul 2 2007, 01:45 PM

USA! I got a hammer with the cars name on it I may not get to it today, but I appreciate all of the input. I am diesel illiterate for the most part.

Posted by: WRX914 Jul 2 2007, 01:53 PM

Posted by: Brian Mifsud Jul 2 2007, 03:32 PM

Posted by: bd1308 Jul 2 2007, 05:04 PM

If you find that the diesel stuff becomes too much of a hassle, I can take that 300D off your hands

Posted by: Dr Evil Jul 3 2007, 12:34 AM

Says the guy with too many unreliable cars and projects Its a 240, not a 300. I think I would have liked the 300 a bit more, but the 240 is effective for what I use it for

Posted by: Dr Evil Jul 4 2007, 02:02 PM

Well genius collective, I cracked all the fuel lines and had Noel crank the engine until fuel came out of all of them. Then hooked them up and experienced a smoother running more powerful running engine

Now for the new question: It is smoking thick BLACK smoke very heavily, how do I fix this? Will this go away on its own? Is this due to it not being run for a long time and maybe having previously uncombusted fuel in the chambers from previous failed attempts to start it?

Posted by: Mr.C Jul 4 2007, 02:59 PM

I would run it for a while and see. Can you adjust the amount of fuel this pump delivers externally? I know with some you can, the VW Rabbit for example. Turn the fuel up and it will smoke badly.
I'm just thinking out loud, but did this come off of a turbo model?

Posted by: Dr Evil Jul 4 2007, 03:04 PM

As far as I know, the fuel can not be adjusted as the cam is set for what it is supposed to be. Not a turbo model, just a lowly 240

Posted by: messix Jul 4 2007, 04:15 PM

i don't know much about benz but there should be a way to adjust the injector pressure on the pump or a regulator.

Posted by: Dr Evil Jul 4 2007, 11:27 PM

Its MFI, I cant find any such adjustment in the literature.